Mooresville developing plan to control stormwater runoff

Seeking to better protect its waterways, Mooresville is beginning to create a comprehensive plan to control an ever-present environmental threat: stormwater runoff.

The master plan will encompass the town’s four drainage basins, which are made up of rivers and their tributaries, examining its underground network of stormwater drainage pipes, many of which are decades old.

It will aim to “find deficiencies in our system so that we can address them before they become significant problems,” town senior engineer Allison Kraft said.

Managing storm water, or rainwater that does not soak into the ground, is a complex challenge facing municipalities big and small.

Help us deliver journalism that makes a difference in our community.

Our journalism takes a lot of time, effort, and hard work to produce. If you read and enjoy our journalism, please consider subscribing today.

It can carry harmful substances into waterways – animal waste, automotive oil, garbage – sweeping them up from impervious surfaces such as parking lots and roads. And it is also problematic outside developed areas, cascading over farmland containing agricultural chemicals such as fertilizers and pesticides.

Besides affecting the ecological health of waterways, it erodes their banks, causing what Kraft described as a “large-scale problem that does not have easy answers.”

The drain pipes throughout town that handle the runoff empty into the nearest body of water.

Many of them are more than 50 years old, Kraft said, so they have probably seen their share of wear and tear. That is particularly true in the eastern part of town, where the infrastructure is generally much older.

For its part, the plan being developed will aim to identify ways to make the drains more efficient, such as by increasing their capacity. But it also will likely lead the town to put in place more stormwater controls, such as rain gardens and riparian buffers – patches of vegetation functioning as miniature ecosystems that soak up pollutants.

It will comprise multiple phases, surveying each basin and seeking public comment. The first, focusing on the Rocky River basin, which includes Coddle and Dye creeks, is expected to take five months or so to complete.

Helping the town put together the plan is the consulting firm ESP Associates P.A. Commissioners approved a nearly $120,000 contract with the company earlier this month.

Anticipating such improvements, the town is collecting monthly fees from owners of all properties in its boundaries that have impervious surfaces of than 400 square feet, setting them aside in a stormwater utility fund. For single-family residences, the fees amount to $3.40 per month.

The fees took effect in January and will remain in place for at least five years, Kraft said.

The ideas to develop the plan and set up the fund were recommended by an advisory committee the town created after it received a water quality permit in 2011 from the state Department of Environment and Natural Resources. Comprising a range of members such as church and school representatives, business owners and residents, the committee also recommended the town hire additional personnel.

The permit requires the town adopt a number of measures to control stormwater runoff, including implementing rules for new development and taking steps to inform the public. One of them calls for “good housekeeping,” requiring regular maintenance of the town’s stormwater drains.

The permit was issued years after the town’s population crossed a threshold set by the U.S. Environmental Protection Agency. The town is scheduled to renew it next year.

While developing the master plan was not among the requirements, it comes at a time when Mooresville is preparing for, and working to encourage, commercial and residential development.

Having a stormwater management plan in place would help protect against environmental degradation, serving to “hold the line and start improvements in water quality,” Department of Environment and Natural Resources spokesman Jamie Kritzer said.